Electromagnetic forming device

ABSTRACT

The present invention is to enable accurate formation of an elongate member while suppressing the occurrence of a shape defect. An electromagnetic forming device is provided with an electromagnetic coil, and a forming mold which is disposed along the electromagnetic coil and provides an elongate material to be formed with a formed shape. An electromagnetic force generated by means of the electromagnetic coil is caused to act on the material to be formed and the material to be formed is pressed onto the forming mold. In the electromagnetic forming device, the forming mold has a cross sectional shape that varies from one end to another in a longitudinal direction of the material to be formed. The forming mold is formed such that, as the material to be formed is moved parallel to the longitudinal direction, the shape of the material to be formed is gradually changed to a desired shape.

TECHNICAL FIELD

The present invention relates to an electromagnetic forming device.

BACKGROUND ART

For example, aircraft components such as a fuselage and a main wing ofan aircraft are configured so that structural members such asplate-shaped skins, elongated frames, and stringers are combined witheach other. The elongated structural member (elongated member) is a moldmaterial, and has a cross-sectional shape whose cross section has aZ-shape, for example. As illustrated in FIG. 16B, the elongated memberincludes those which have a plurality of steps (joggles) in which aplate thickness is changed at each site along a longitudinal direction.An elongated member 60 illustrated in FIG. 16B has a thick plate portion61 and a thin plate portion 62.

In a case of manufacturing the elongated member having a cross-sectionalshape bent in the Z-shape, as illustrated in FIG. 16A, roll forming isperformed on an elongated material 50 having a flat plate shape which isnot bent. In a roll forming device which performs the roll forming,multiple sets of two rolls interposing the elongated member therebetweenare installed along a line.

The elongated material is caused to sequentially pass from one end sideto the other end side of the line in which the multiple sets of rollsare installed. In this manner, the elongated material is graduallyformed from a cross-sectional shape having the flat plate shape to across-sectional shape required as a product. In this way, the elongatedmaterial is gradually formed using the multiple sets of rolls.Accordingly, it is possible to prevent defect occurrence such as crackscaused by a rapid change in the cross-sectional shape.

CITATION LIST Patent Literature

[PTL 1] Japanese Unexamined Patent Application Publication No.2007-296553

[PTL 2] Japanese Unexamined Patent Application Publication No. 6-23442

SUMMARY OF INVENTION Technical Problem

However, in a case where the elongated material is formed by performingthe above-described roll forming, distortion and residual stress occurin the formed elongated member due to wear of a roll or a subtle changein a pressure mechanism which applies pressure to the roll.Consequently, shape defects such as twisting, warping (horizontalwarping or vertical warping), and waving occur. In addition, dependingon a degree of the wear or the change in the applied pressure, thedistortion or the residual stress occurring in each material may differ,thereby causing a possibility that the shape may be changed in variousways including the twisting, the warping, or the waving.

Furthermore, in a case where the cross-sectional shape to be obtainedafter forming is changed, the roll forming device needs to replace theroll in accordance with the shape. In an initial stage after thereplacement, the above-described shape defect is likely to occur. It isnecessary to adjust the role or the pressure mechanism.

Furthermore, in a case of the elongated member in which the plurality ofsteps are formed in the longitudinal direction, a pressing way of theroll differs between the thick plate portion and the thin plate portion.Therefore, in some cases, a bending angle may not be a predeterminedangle in each site. In addition, in the roll forming, the elongatedmember passes through the two rolls arranged up and down. Accordingly,as illustrated in FIG. 17A, one surface side is less likely to serve asa step surface, and the other surface side is less likely to serve as aflat surface. As illustrated in FIG. 17B, the step surface is alsoformed on the other surface side. As a result, when the elongated memberhaving the plurality of steps are combined with the other member so asto be assembled together as an aircraft component, a gap is generatedbetween the elongated member and the other member.

On the other hand, a technology is known in which a forming targetmaterial is formed using an electromagnetic forming device instead ofthe roll forming device. However, no technology is known in whichforming an elongated material is formed so as to have a cross-sectionalshape bent in the Z-shape or the forming is performed on the elongatedmember having the plurality of steps. PTL 1 described above discloses atechnology in which a thin plate is formed into a desired shape by usingthe electromagnetic forming device. PTL 2 discloses a technology inwhich an electromagnetic force is applied in a multistage manner to apredetermined portion of a hollow material by using an electromagneticplastic processing method.

The present invention is made in view of the above-describedcircumstances, and an object thereof is to provide an electromagneticforming device which can perform highly accurate forming by preventing ashape defect in forming an elongated member.

Solution to Problem

According to an aspect of the present invention, there is provided anelectromagnetic forming device including an electromagnetic coil, and aforming die installed along the electromagnetic coil so as to provide aformed shape for a forming target material having an elongated shape. Anelectromagnetic force generated by the electromagnetic coil is appliedto the forming target material so that the forming target material ispressed against the forming die. The forming die has a cross-sectionalshape which differs from one end side thereof toward the other end sidethereof along a longitudinal direction of the forming target material.In the forming die, the forming target material moves parallel to thelongitudinal direction so that the forming target material is graduallyformed and changed to have a desired shape.

According to this configuration, the electromagnetic force generated byperforming the electromagnetic coil is applied to the forming targetmaterial having the elongated shape, and the forming die provides theformed shape for the forming target material. The forming die has thecross-sectional shape which differs from one end side to the other endside along the longitudinal direction of the forming target material.The forming target material moves parallel to the longitudinal directionso that the forming target material is gradually formed and changed tohave the desired shape. In this manner, the forming target material ismoved parallel to the longitudinal direction so that the electromagneticforce is repeatedly applied to the forming target material. Accordingly,the forming target material deformed by being pressed against theforming die is gradually changed to have the desired shape.

In the above-described aspect, the electromagnetic coil may becontinuously formed along the forming die.

In the above-described aspect, the electromagnetic coils may berespectively installed at a plurality of locations. The plurality ofelectromagnetic coils may be respectively shorter than the formingtarget material, and may be installed along the longitudinal directionof the forming target material.

In the above-described aspect, a plurality of the forming dies may beinstalled. The plurality of forming dies may be respectively shorterthan the forming target material, and may be installed along thelongitudinal direction of the forming target material.

In the above-described aspect, the plurality of forming dies may have aninclined surface formed in an end portion.

In the above-described aspect, the plurality of forming dies may beformed so that the forming target material is provided with a recessedshape or a projecting shape in the longitudinal direction.

Advantageous Effects of Invention

According to the present invention, highly accurate forming can beperformed by preventing a shape defect in forming an elongated member.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration diagram illustrating anelectromagnetic forming device according to a first embodiment of thepresent invention.

FIG. 2 is a schematic configuration illustrating a modification exampleof an electromagnetic coil of the electromagnetic forming deviceaccording to the first embodiment of the present invention.

FIG. 3 is a perspective view illustrating a forming die of theelectromagnetic forming device according to the first embodiment of thepresent invention.

FIG. 4 is a plan view illustrating the forming die of theelectromagnetic forming device according to the first embodiment of thepresent invention.

FIG. 5 is a front view illustrating the forming die of theelectromagnetic forming device according to the first embodiment of thepresent invention.

FIG. 6 is a front view illustrating the forming die of theelectromagnetic forming device according to the first embodiment of thepresent invention.

FIG. 7 is a front view illustrating the forming die of theelectromagnetic forming device according to the first embodiment of thepresent invention.

FIG. 8 is a plan view illustrating the forming die of theelectromagnetic forming device according to the first embodiment of thepresent invention.

FIG. 9 is a front view illustrating the forming die of theelectromagnetic forming device according to the first embodiment of thepresent invention.

FIG. 10 is a longitudinal sectional view illustrating the forming die ofthe electromagnetic forming device according to the first embodiment ofthe present invention, and is a view taken along arrow X-X in FIG. 6.

FIG. 11 is a longitudinal sectional view illustrating the forming die ofthe electromagnetic forming device according to the first embodiment ofthe present invention, and is a view taken along arrow XI-XI in FIG. 8.

FIG. 12 is a longitudinal sectional view illustrating the forming die ofthe electromagnetic forming device according to the first embodiment ofthe present invention, and is a view taken along arrow XII-XII in FIG.8.

FIG. 13 is a perspective view illustrating a forming die of anelectromagnetic forming device according to a second embodiment of thepresent invention.

FIG. 14 is a plan view illustrating the forming die of theelectromagnetic forming device according to the second embodiment of thepresent invention.

FIG. 15 is a front view illustrating the forming die of theelectromagnetic forming device according to the second embodiment of thepresent invention.

FIG. 16A is a perspective view illustrating an elongated material.

FIG. 16B is a perspective view illustrating the elongated material.

FIG. 17A is a perspective view and a partial side view illustrating theelongated member.

FIG. 17B is a perspective view and a partial side view illustrating theelongated member.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments according to the present invention will bedescribed with reference to the drawings.

First Embodiment

Hereinafter, a first embodiment according to the present invention willbe described with reference to FIGS. 1 to 12. As illustrated in FIG.16A, an electromagnetic forming device 1 according to the presentembodiment uses a forming die 4 so as to provide a cross-sectionalshape, for example, a Z-shape, for an elongated material 50 serving as aforming target material made of an aluminum alloy, for example. Asillustrated in FIG. 16B, an elongated member 60 formed by performing theelectromagnetic forming device 1 is used as a structural member such asa frame and a stringer which configure aircraft components such as afuselage and a main wing of an aircraft.

As illustrated in FIG. 1, the electromagnetic forming device 1 accordingto the present embodiment has an electromagnetic coil 2, a power supplyunit 3 for supplying an electric current to the electromagnetic coil 2,and the forming die 4.

The electromagnetic coil 2 is continuously formed along the forming die4. For example, as illustrated in FIG. 1, the electromagnetic coil 2 mayhave a cylindrical shape, and a cross-sectional shape thereof may becircular. As illustrated in FIG. 2, the electromagnetic coil 2 may belocated along a surface of the forming die 4.

A large current is supplied to the electromagnetic coil 2 from the powersupply unit 3. A power supply circuit 5 is configured to include acircuit as follows. For example, as illustrated in FIG. 1, a capacitor 6is installed in parallel with the electromagnetic coil 2. A switch 7 isinstalled between a connection point of the power supply unit 3 and thecapacitor 6 and the electromagnetic coil 2. In this configuration, whenthe switch 7 is turned on, the capacitor 6 is electrically charged fromthe power supply unit 3 via an electric resistance 8. Then, the switch 7is turned off, and the capacitor 6 is electrically discharged, therebygenerating the large current to the electromagnetic coil 2.

The large current is instantaneously applied to the electromagnetic coil2, thereby generating an induced current on a surface of the elongatedmaterial 50 located along the electromagnetic coil 2. As a result, anelectromagnetic force is applied to the surface of the elongatedmaterial 50, and the elongated material 50 moves in a direction of theforming die 4 so as to be pressed against the forming die 4.

The forming die 4 is installed along the longitudinal direction of theelongated material serving as the forming target material. The formingdie 4 provides the formed shape for the elongated material. In order toprevent defect occurrence such as cracks caused by a rapid change in thecross-sectional shape, as illustrated in FIGS. 3 to 5, the forming die 4has a cross-sectional shape which differs from one end 4 a side towardthe other end 4 b side along the longitudinal direction of the elongatedmaterial 50. That is, as illustrated in FIGS. 4 to 9, the elongatedmaterial 50 moves parallel to the longitudinal direction. In thismanner, the elongated material 50 is formed so as to be graduallychanged to the desired shape.

For example, the electromagnetic coil 2 and the forming die 4 havesubstantially the same length as the elongated material 50. Withoutbeing limited to a case where only one electromagnetic coil 2 iscontinuously formed in the longitudinal direction, the electromagneticcoil 2 may be divided into a plurality of pieces in the longitudinaldirection. In this case, the plurality of electromagnetic coils 2 aredisposed to be separate from each another.

A forming method of the formed elongated member 60 (refer to FIG. 16B)will be described with reference to FIGS. 3 and 10 to 12. The elongatedmember 60 has horizontal flange portions 63 and 64, and a web portion 65which forms an angle of 90° with the flange portions 63 and 64. Asillustrated in FIG. 3, a forming surface 9 a on one end 4 a side in theforming die 4 has a horizontal flat surface shape. Then, a formingsurface 9 b for forming the web portion 65 on the forming surface 9 ofthe forming die 4 has the same width from one end 4 a side to the otherend 4 b side, and an inclination angle thereof is constant while ahorizontal state is maintained. Forming surfaces 9 c and 9 d for formingthe flange portions 63 and 64 have the same width from one end 4 a sideto the other end 4 b side, and an inclination angle thereof is graduallyinclined from the horizontal state to a vertical state.

In an electromagnetic forming method using the electromagnetic formingdevice 1 according to the present embodiment, first, as illustrated inFIGS. 4 and 5, only one end 50 a side of the flat plate-shaped elongatedmaterial 50 is one end 4 a of the forming die 4 is installed on one end4 a side of the forming die 4. Then, the current is supplied to theelectromagnetic coil 2, and the elongated material 50 is pressed againstthe forming die 4. As a result, as illustrated in FIGS. 4 and 5, one end50 a of the elongated material 50 is formed along the forming die 4.

Thereafter, as illustrated in FIGS. 6 and 7, the elongated material 50is shifted to the other end side as much as a predetermined distancealong the longitudinal direction. Then, the current is supplied to theelectromagnetic coil 2, and the elongated material 50 is pressed againstthe forming die 4. As a result, the elongated material 50 is shifted inthe longitudinal direction. In this manner, the flat plate-shapedelongated material 50 falling within a range of the electromagnetic coil2, and one end 50 a side of the elongated material 50 previously formedalong the forming die 4 are formed along the forming die 4.

The above-described procedure is repeatedly performed, thereby causingthe elongated material 50 to gradually deform into a final shape fromthe one end 50 a side to the other end 50 b side. The elongated material50 passing through the other end 4 b side of the forming die 4 has thefinal shape obtained by performing the electromagnetic forming. Untilthe other end 50 b of the elongated material 50 completely passestherethrough, the forming is repeatedly performed by shifting theposition of the elongated material 50 and supplying the current to theelectromagnetic coil 2. If the other end 50 b of the elongated material50 completely passes therethrough, the elongated member 60 has the finalshape obtained by performing the electromagnetic forming over the entirelongitudinal direction of the elongated material 50 (refer to FIG. 16B).

As described above, according to the electromagnetic forming using theelectromagnetic forming device 1 of the present embodiment, a mold isless worn compared to the roll forming, and a compression mechanism suchas the roll forming device is not provided. Accordingly, during theforming, there is no subtle change in the compression mechanism.Therefore, the shape defect is less likely to occur in the elongatedmember 60 formed by performing the electromagnetic forming. In addition,the forming die 4 has a continuous shape in the longitudinal direction.Accordingly, a setup time for roll clearance adjustment in the rollforming device can be reduced.

Furthermore, the forming is performed at high speed by utilizing theelectromagnetic force. Accordingly, a spring-back volume can be reduced,the forming can be highly accurately performed, and work for correctingdistortion after the forming can be reduced.

Second Embodiment

Next, a second embodiment according to the present invention will bedescribed with reference to FIGS. 13 to 15. In the above-described firstembodiment, a case of using the forming die 4 having the continuousshape in the longitudinal direction has been described. However, thepresent invention is not limited to this example.

The forming die 4 according to the second embodiment of the presentinvention is divided into a plurality of pieces in the longitudinaldirection, and split molds 10A, 10B, and 10C are arranged to be separatefrom each other. In this manner, cost can be reduced, compared to a caseof using the forming die 4 having the continuous shape in thelongitudinal direction.

The electromagnetic coil 2 is divided into each position correspondingto the respective split molds 10A, 10B, and 10C, and the respectivesplit molds 10A, 10B, and 10C are installed to be separate from eachother. The forming die 4 and the electromagnetic coil 2 are divided intothree in an example illustrated in FIG. 13, but may be divided into two,and four or more.

A forming surface 11 of the split molds 10A, 10B, and 10C has a formingsurface 11 a for forming the web portion 65, a forming surface 11 b forforming the flange portion 63, and a forming surface 11 c for formingthe flange portion 64. In the respective split molds 10A, 10B, and 10C,the forming surfaces 11 a, 11 b, and 11 c have the same width from oneend side to the other end side. The present invention is not limited tothis example. As in the first embodiment, the forming surfaces 11 b and11 c may be gradually inclined from one end side to the other end side,and the inclination angle may be gradually inclined from the horizontalside to the vertical side.

An end portion of the forming surface 11 a for forming the web portion65 in the respective split molds 10A, 10B, and 10C may have a taperedsurface 11 d inclined toward the adjacent split molds 10A, 10B, and 10C.In this manner, the elongated material 50 can be smoothly moved withoutthe elongated material 50 being caught thereon.

According to the present embodiment, as in the first embodiment, thefollowing procedure is also repeated performed. The current is suppliedto the electromagnetic coil 2 so that the elongated material 50 ispressed against the forming die 4. Thereafter, the elongated material 50is shifted to the other end side as much as the predetermined distancealong the longitudinal direction. FIGS. 14 and 15 illustrate an exampleof a positional relationship between the elongated material 50 and thesplit molds 10A, 10B, and 10C during the forming.

Then, the elongated material 50 is caused to gradually deform into thefinal shape from the one end 50 a side to the other end 50 b side.

The elongated material 50 formed according to the present embodiment mayhave a uniform thickness in the longitudinal direction. Alternatively,as illustrated in FIG. 16A, the elongated material 50 may have aplurality of steps (joggles) in which the plate thickness is changed ateach site along the longitudinal direction. In this case, when theelongated material 50 is formed by performing the electromagneticforming, the forming surfaces 11 a, 11 b, and 11 c of the respectivesplit molds 10A, 10B, and 10C may have a recessed shape or a projectingshape corresponding to each shape of the plurality of steps so that theplurality of steps are formed in the longitudinal direction. In thismanner, the electromagnetic forming device 1 not only provides thecross-sectional shape of the Z-shape, but also simultaneously forms theplurality of steps in the longitudinal direction. Therefore, the formingprocess can be reduced, and the cost can be reduced.

In a case of the present embodiment, compared to the first embodimentadopting the forming die 4 having the continuous shape in thelongitudinal direction, the cost for manufacturing the forming die 4 canbe reduced. In addition, as in the first embodiment, the mold is lessworn compared to the roll forming, and the compression mechanism such asthe roll forming device is not provided. Accordingly, during theforming, there is no subtle change in the compression mechanism.Therefore, the shape defect is less likely to occur in the elongatedmember 60 formed by performing the electromagnetic forming. In addition,the forming is performed at high speed by utilizing the electromagneticforce. Accordingly, a spring-back volume can be reduced, the forming canbe highly accurately performed, and work for correcting distortion afterthe forming can be reduced.

REFERENCE SIGNS LIST

1: electromagnetic forming device

2: electromagnetic coil

3: power supply unit

4: forming die

5: power supply circuit

6: capacitor

7: switch

8: electric resistance

9: forming surface

9 a, 9 b, 9 c, 9 d: forming surface

10A, 10B, 10C: split mold

11: forming surface

11 a, 11 b, 11 c: forming surface

11 d: tapered surface

50, 60: elongated material

61: thick plate portion

62: thin plate portion

63, 64: flange portion

65: web portion

1. An electromagnetic forming device comprising: an electromagneticcoil; and a forming die installed along the electromagnetic coil so asto provide a formed shape for a forming target material having anelongated shape, wherein an electromagnetic force generated by theelectromagnetic coil is applied to the forming target material so thatthe forming target material is pressed against the forming die, whereinthe forming die has a cross-sectional shape which differs from one endside thereof toward the other end side thereof along a longitudinaldirection of the forming target material, and wherein in the formingdie, the forming target material moves parallel to the longitudinaldirection so that the forming target material is formed to be graduallychanged into a desired shape.
 2. The electromagnetic forming deviceaccording to claim 1, wherein the electromagnetic coil is continuouslyformed along the forming die.
 3. The electromagnetic forming deviceaccording to claim 1, wherein a plurality of the electromagnetic coilsare installed, and wherein the plurality of electromagnetic coils arerespectively shorter than the forming target material, and are installedalong the longitudinal direction of the forming target material.
 4. Theelectromagnetic forming device according to claim 1, wherein a pluralityof the forming dies are installed, and wherein the plurality of formingdies are respectively shorter than the forming target material, and areinstalled along the longitudinal direction of the forming targetmaterial.
 5. The electromagnetic forming device according to claim 4,wherein the plurality of forming dies have an inclined surface formed inan end portion.
 6. The electromagnetic forming device according to claim4, wherein the plurality of forming dies are formed to give the formingtarget material a recessed shape or a projecting shape in thelongitudinal direction.